Propeller with propellers

I've been working on a quad-rotor project for a while, but the Propeller chip made my life a lot easier.· Remote control in and servo output each on their own cogs is a LOT easier and more accurate than using interrupts.· It's not finished yet, but I've now had my first few successful flights in my garage.

It's finished in the sense that it now flies and is reasonably stable. Prior to posting I hadn't read the rules on finished/unfinished, so I apologize. I will comment the full code enough that others should be able to read it, and will post the schematic and code for what you see in the video.

It's unfinished in that I want to add self-levelling to the flight control loop, and the plan is for this to ultimately have moveable rotors (like an Osprey) and real wings, so it'll fly normally, or do VTOL. I figured the VTOL part would be the hardest, so I did that first.

The receiver is a Spektrum AR6200, but anything should work. Motors are indeed brushless. Motors are 1050Kv, 20A max, and I'm using TowerPro 20A brushless speed controls. A pair of 3 cell, ThunderPower 2070 batteries in parallel gives it about 4.1Ah of power, and I have yet to figure out my power draw exactly. At 2 Lbs, 13 oz, it's pretty heavy with the packs loaded, but it hovers at approximately 1/2 throttle.

I haven't figured out the flight duration, but I suspect it's around 6 minutes or so. To be fair, I'm not using the most efficient prop for this kind of flight. I think my props are 8.5x6, but if I were to go to a lower pitch with larger diameter it would be more efficient. Ultimately I want the thing to do 'plane like' flight as well as hover, so I wanted the props to balance between fast forward flight and decent hover performance. If I was going for JUST hover performance, lower KV motors and 10x4 props would probably be much better for payload capacity and flight time.
Also, the platform is still somewhat unstable, though that's in my garage in a lot of propwash, so it might not be as bad as I think.· I fly R/C helicopters, so I'm pretty good at controlling the thing.· This would not be something I'd recommend for someone with no flight experience.· If and when the self-levelling works it'll be easier to handle.

No problem. I've update the original post to include the full code and schematic. I flew it outside for a few minutes today, and even with a small breeze it was more stable than it was indoors. Still a little twitchy, but I'm working on it.

I am not able to view the schematic using gEDA schematic editor in Linux. Can you post it as a jpg?
Item 2 is the wire extending from the bottom of the aircraft. Is it for stabilization or is it an antenna extension?

I am not able to view the schematic using gEDA schematic editor in Linux. Can you post it as a jpg?
Item 2 is the wire extending from the bottom of the aircraft. Is it for stabilization or is it an antenna extension?

Ron

The schematic was created with EaglePCB.· I'll post a JPG when I get home tonight, and the wire you mention is just the battery leads for the motors.· The receiver antennas are only an inch long (there are 4 of them).

Thanks Tom C.I have been using a Spektrum DX-6 for a couple of years now in my surface boats, and just picked up a 6i. What I would like to do is to somehow lenghten the antenna so i could run it up a periscope and use it on the submarines too.

I suspect that the receiver antennas are 1/4 wave given their short length. As you can see, the AR6200 uses two receivers due to the directionality of the 2.4GHz signal compared to a 72/75 MHz signal.

If you need a longer antenna you might have to retrogress back to 72/75 MHz where the receivers use a long wire antenna that might be a 1/4 wave or even 1/2 wave.

I am presently using a Spektrum DX6i and a BR6000 which is a nice combination for a rover robot. I am able to control the DX6i with my PC through an Endurance R/C PCTx. If I can duplicate Jason's Propeller heliplatform, I plan to buy a AR6200 to go with my DX6i.

Just a thought.

Regards,
TCIII

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If you are going to send·a Robot·to save the world, you·better make sure it likes it the way it is!

It's worth noting that the AR6200 (and many other Spektrum receivers) use multiple receiver modules and choose the best signal among them.· The connector for the 'outrigger' is 3 wires, presumably power, ground, and signal.· You could probably extend the lines to the 2nd receiver and put the whole thing, antennas and all, into the head of a periscope (if it was large enough).· You could remove the case to cut the size down a little.

I'm considering hooking it up to a scope to see if·I can figure out what the protocol is.· It'd be nice to have·an I2C or SPI receiver instead of having to interpret pulse widths.· :)

I want to start working on the airframe now, but to me that's more daunting than the electronics. The motors rotate forward for normal flight, and up to hover. I've been working on getting the 'static motor' version as stable as possible before I move on. I'd like to be able to hover it hands off, though it's actually quite stable now. I'll take a new video in a few days if I have time. I reduced the weight of the propellers, so the motor response is quicker, and I added code to 'help' level it, using the accelerometer and Kalman filters. If I turn it up too high it starts to oscillate, but even with it set low it helps quite a bit.

I'll post more as it happens. Thanks for the encouragement, everyone. Thanks especially to Parallax for this very cool chip. This is my 3rd quadrotor, and the Propeller-based version was the simplest to code by far, and the most fun. I get to spend more time tweaking and less time figuring out how to drive servos, read RC inputs, and do math on one thread. :)

Jason - I believe in a desing like this two of the propellers rotate in one direciton and the other two rotate in the opposite direction. Or maybe they have a differenet blade or pitch or something like that. What did you do with yours?

BTW, YouTube is a breeze.· They now have a high resolution viewing option to if you upload your video in a high res format.